Doing the right thing for whom? The Tories?
If you deconstruct May's announcement, it's quite clearly nonsense. (Hope she had her fingers crossed while the word came out of her mouth.) The people threatening May aren't the opposition party, but her own back benchers. They rebelled on the budget and are threatening to rebel over grammar schools.
A new government will mean that the manifesto promises not to increase TAX or VAT or abolish the triple lock will no longer count.
May knows perfectly well that the economy is facing problems and that her hands are tied without being able to raise extra cash. She aslo knows that the public is opposed to "hard Brexit", so she wants an election before even more people realise the consequences.
Just one month ago she said that a snap election would destabilise the country. Margaret (TINA) Thatcher will be turning in her grave.
I'm sure the Conservatives will remain the biggest party, it really depends whether Labour can hold its seats. The pundits think they won't gain (m)any. However, although they have an historically low number of voters, the way the voters are distributed means they might not lose many seats.
The threat is likely to come from the LibDems in places like Twickenham, Bath and Cheltenham, which were LibDem, voted Remain and only need a small swing for the LibDems to retake them.
We could end up with May as leader of the biggest party and still PM, but if Labour and the LDs come to some kind of agreement (not a coalition) they could block the Conservatives in Parliament.