Losing Power on Nixie Tube when Plugging in LCD Touch Shield

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The title gives you the gist of the problem. Let me be more specific here. I'll start with the hardware. I'm using the parts in Mega 2560 R3 Starter Kit | SainSmart – SainSmart.com kit, plus a few little modifications I've made, such as soldering in a few pins onto the existing pins to add an extra connection. Next, here's the code. I apologize if it's a bit long. The idea is just that the Nixie tube counts up, then restarts. No big deal, right?

int a=7;  //Top Horizontal
int b=6;  //Top-Right
int c=5;  //Bottom-Right
int d=11;  //Bottom Horizontal
int e=10;  //Bottom-Left
int f=8;  //Top-Left
int g=9;  //Middle Horizontal
int dp=4; //Decimal Point

//display number0
void digital_0(void)
{
  unsigned char z;
  for(z=4;z<=8;z++)
  digitalWrite(z,HIGH);
  digitalWrite(d,HIGH);
  digitalWrite(e,HIGH);
  digitalWrite(g,LOW);
}

//display number1
void digital_1(void)
{
  unsigned char z;
  digitalWrite(c,HIGH);// pin5 high, light up c
  digitalWrite(b,HIGH);//light up b
  for(z=7;z<=11;z++)//go out else
    digitalWrite(z,LOW);
    digitalWrite(dp,HIGH);//light up decimal point dp
}

//display number2
void digital_2(void)
{
  unsigned char z;
  digitalWrite(b,HIGH);
  digitalWrite(a,HIGH);
  for(z=9;z<=11;z++)
    digitalWrite(z,HIGH);
    digitalWrite(dp,HIGH);
    digitalWrite(c,LOW);
    digitalWrite(f,LOW);
}

// display number3
void digital_3(void)
{
  unsigned char z;
  digitalWrite(g,HIGH);
  digitalWrite(d,HIGH);
  for(z=5;z<=7;z++)
    digitalWrite(z,HIGH);
  digitalWrite(dp,HIGH);
  digitalWrite(f,LOW);
  digitalWrite(e,LOW);
}

// display number4
void digital_4(void)
{
  digitalWrite(c,HIGH);
  digitalWrite(b,HIGH);
  digitalWrite(f,HIGH);
  digitalWrite(g,HIGH);
  digitalWrite(dp,HIGH);
  digitalWrite(a,LOW);
  digitalWrite(e,LOW);
  digitalWrite(d,LOW);
}

// display number5
void digital_5(void)
{
  unsigned char z;
   for(z=7;z<=9;z++)
    digitalWrite(z,HIGH);
   digitalWrite(c,HIGH);
   digitalWrite(d,HIGH);
   digitalWrite(dp,HIGH);
   digitalWrite(b,LOW);
   digitalWrite(e,LOW);
}

// display number6
void digital_6(void)
{
  unsigned char z;
  for(z=7;z<=11;z++)
    digitalWrite(z,HIGH);
  digitalWrite(c,HIGH);
  digitalWrite(dp,HIGH);
  digitalWrite(b,LOW);
}

// display number7
void digital_7(void)
{
  unsigned char z;
  for(z=5;z<=7;z++)
    digitalWrite(z,HIGH);
  digitalWrite(dp,HIGH);
  for(z=8;z<=11;z++)
    digitalWrite(z,LOW);
}

// display number8
void digital_8(void)
{
  unsigned char z;
  for(z=5;z<=11;z++)
    digitalWrite(z,HIGH);
  digitalWrite(dp,HIGH);
}

//digital number9
void digital_9(void)
{
  unsigned char z;
  digitalWrite(g,HIGH);
  digitalWrite(d,HIGH);
  for(z=5;z<=7;z++)
    digitalWrite(z,HIGH);
  digitalWrite(dp,HIGH);
  digitalWrite(f,HIGH);
  digitalWrite(e,LOW);
}

void setup()
{
  int i;//define i
  for(i=4;i<=11;i++)
    pinMode(i,OUTPUT);//set pin4~pin11 output
}
void loop()
{
  while(1)
  {
    digital_0();//display 0
    delay(1000);//delay 1s
    digital_1();
    delay(1000);
    digital_2();
    delay(1000);
    digital_3();
    delay(1000);
    digital_4();
    delay(1000);
    digital_5();
    delay(1000);
    digital_6();
    delay(1000);
    digital_7();
    delay(1000);
    digital_8();
    delay(1000);
    digital_9();
    delay(1000);
  }
}

This all works just fine, when it's just the Nixie tube hooked up. Now, when I hook up the LCD touch shield shown in the kit, I immediately lose power to pins 4, 5, and 6. The rest of the code keeps going and all of the rest of the lines on the display light up, and I even get power to the LCD (it lights up), but I'm losing power through those 3 pins. Any idea what's going on?

EDIT: Nevermind. I figured it out. I followed the wiring diagram in one of the SainSmart tutorials and it didn't wire up the second common cathode on the nixie tube, resulting in a greatly dimmed display (which I didn't notice because I didn't know the thing was supposed to be so freaking bright) and not enough power to power the LCD and the tube from the single cathode. Figured I would delete the post, but maybe someone will learn from my mistake!

EDIT2: Now that I have power to both, I am noticing that I cannot use the touch screen when the nixie tube is drawing power. Is there any way that I can compensate for this? Nixie tube is attached to pins 4-11, then to the ground and the 3.3V port. As soon as I unplug the ground, the touchscreen works fine, but until then it will not respond at all. Help?