
I currently own two young male rats- about 5-6 months old- Anatole and Dolokhov. Anatole is fine with Dolokhov and they get along great, but is very unpredictable with people and has bitten both me and my wife more than once, drawing blood every time. However he never shows signs of aggression before biting, he just chomps down.

I have just rescued two adult (1 year) boys from someone today and am hoping to be able to integrate them into my existing pair if possible. They seem like gentle enough lads, one is very skittish with being handled at the moment but he's never met me before and he's in a new place, so I'm hoping he'll calm down. But Anatole seems quite fixated on them from his cage- digging at the bars, sniffing, fur a little up- and I'm a little concerned that introductions may go badly.
My question is, how can I do my utmost to alleviate any potential issues when introducing these lads? This is the first time I've introduced 1yr+ adult rescues to existing rats- I usually put them in the empty bath and let them meet each other for a first stage, but with Anatole being hard to handle I worry about getting the others out in time if he attacks. Any tips or tricks of the trade? (Other than a long pole and a leather suit?)

I have no indication that Anatole is specifically rat aggressive at all, as I say he and Dolokhov are fine, but I would hate to have any serious injuries happen.
Anatole IS booked in for a neuter later this month; ideally I was hoping to get everyone introduced before then because the cage these boys arrived in is not hugely suitable long term, but do you think it would be better to do it after his hormones have had a chance to settle?
Thanks everyone.