ApigeeX : sequencedRollout + override

Hi! We are trying to understand sequencedRollout during ApigeeX deployment.

We have below proxies deployed in both dev and uat:

Proxy 1 Base: /basepath/apigeex

Proxy 2 Base path proxy 2: /basepathapigeex/*/dup-proxy

We have setup 1 environment group (my-env-grp-nonprod) consists of 4 environments (dev, sit, pst,uat)

What we have observed is that with override=true and sequencedRollout=true during deployment of proxy1 for example, new API calls to proxy 1 remains in same environment and proxy. There are no significant delays as well considering the elapsed time of each API call. 

May you please clarify the following :

1. with override=true and sequencedRollout=true, in the scenario that proxy1 has some connection issues or is down for few milliseconds during deployment in dev, will the API traffic of proxy 1 get routed to uat environment during those time? what is the expectation considering this scenario?

2. could you please elaborate or provide more information on how sequencedRollout works?

3. what are the implications on using sequencedRollout=true + override=true?