I think what happened in today's nominations is a repercussion of Saturday's episode with Salman. Its worth mentioning that Saturday is the only day the housemates get to talk with someone(host) from outside the BB house and when they interact with the host they get the idea of who is getting portrayed in a negative/positive image based on the host's behavior with them. Then they pick out the targets based on that.
e.g.- even after breaking things of BB house when Shilpa's looks were compared with Aishwarya Rai by the host, everyone thought Shilpa has a very positive image outside and refrained from voting her.
Allow me to point out what happened during last Saturday's episode with Salman which may had an impact on nominations this week..
1. Ratan was ridiculed by the host after performing brilliantly in the task.
Result- Ratan gets nominated.
2. Pratyusha gets humiliated and was called liar by the host because she cried during electric shock.
Result- Pratyusha gets nominated.
3. Andy was rebuked by the host for not attempting the electric shock challenge.
Result- Andy gets nominated.
4. Anita Advani calls Arman a liar (rightfully) only exception here is.. this was shown on Sunday's episode.
Result- Arman gets nominated.
5. the host spends a lot of time praising last week's worst performer Elli's looks thereby indicating he has a weakness for her.
Result- Elli is spared by other contestants they dont want to incur the wrath of the host who has a major say in BB (read influx of his friends Mahek Chahel, Hazel Keech, Rajat Rawail and others in BB house since season 5)
I think the host's treatment to the contestants on Saturday indicates who gets nominated in the following week.