It would be great if, in addition to your current collision detection you could see an indicator in tickets and ticket search results that someone is looking at a ticket.

In Zendesk you can see who is even looking at a ticket either in the different ticket views or when you are in the ticket itself. This is live-updated so you could see as soon as someone comes and goes from what you are looking at. Freshdesk do a nice job of this too.

This way you can skip even looking at / reading a ticket and deciding if you can or should take it, if someone is looking at it already.