Killing players is poor form despite the fact it can be thematically appropriate, teleporting players is sloppy and very infuriating when it's you that it happens to (the point is capped, you're a foot away from the spawndoor about to back up your team and ZAP gotta walk for another 30 seconds)
I'd recommend doing what Borneo does and disable the respawn brush, lock the door open and sink the resupply cabinet into the ground.
(send 'kill' to the respawn brush, tell the door prop to play the open anim and the brush door to 'open', send 'kill' to the door trigger and lastly parent the resupply cabinet to a func_door that sinks into the ground)
This method allows players who are halfway to the door to leave without getting zapped away and it allows any player who is afk to be killed by an advancing team, it also prevents the room being hidden in.
It's what I'm doing in ququmannz and (excepting where I had some issues with the names of my doors) it's worked perfectly.
Coincidentally this is also what Overwatch does.