Simple Security System

#include <EEPROM.h>

int door1, door2, timer_cnt, chk;
boolean lock=true, alarm=false;

void setup() {
  pinMode(2,OUTPUT); //lock
  pinMode(4,OUTPUT); //alarm
  pinMode(12,INPUT); //proximity-1
  pinMode(13,INPUT); //proximity-2
  
  digitalWrite(2,HIGH);
  digitalWrite(4,LOW);
}

void loop() {
  door1=digitalRead(12);
  door2=digitalRead(13);
  if (door1 && door2){ //both doors closed
    digitalWrite(2,HIGH); //lock is activated
    timer_cnt=0;
  }
  else{ //one of doors is open
    digitalWrite(2,LOW); //lock is deactivated
    lock=false;
  }
  if (!lock){ //door is open
    timer_cnt=EEPROM.read(0);
    timer_cnt=timer_cnt+1;
    EEPROM.write(0, timer_cnt);
    chk=EEPROM.read(0);
    if (chk>=254 || alarm){ //timer is up
      digitalWrite(4,HIGH); //turn on alarm
      alarm=true;
    }
    else{
      digitalWrite(4,LOW); //turn off alarm
      alarm=false;
    }
  }
  else {
    timer_cnt=0;
    EEPROM.write(0, timer_cnt);
    lock=true;
  }
}