In her letter to Rand, Mo said she saw (on her trip to Rhuidean, which she didnt' tell Rand, but which we know) 3 possible outcomes at the docks:

1. Rand's death.
2. Rand becoming Lanfear's lover.
3. What actually ended up happening.

We don't know how many different scenarios lead to #1 or #2, but I would say it's safe to assume that Mo deciding to use the angreal, rather than setting it up for Lanfear to use, likely did. Otherwise, she would have chosen that option, obviously.

The bottom line is, of all the possible scenarios Mo foresaw with respect to her actions at the docks, #3 was the best result for Rand, not necessarily for her. There is no reason for us to think that she saw anything beneficial to herself in #3 (like becoming stronger), other than what we know already - she saw the possibility of surviving the ordeal, as she explained in her note to Thom.