No, it's definitely not safe. People get picked off the streets (3-4 riot cops against each one), brutally beaten (not all, but many), and thrown in jail for a few hours to a few days. Some lose their jobs after that.
Some even lose their jobs for posting anti-war comments on the internet:
https://novayagazeta.ru/articles/2022/03/01/iavnoe-neuvazhen...
Here's another example — an 80 year old lady was picked off the street and thrown in jail with the rest of them. Twice:
https://novayagazeta.ru/articles/2022/02/27/v-avtozake-kolle...
What's ironic here is she was born in besieged Stalingrad in 1942. Think about it: they've jailed a siege survivor from the Great Patriotic War which they are so proud of for standing peacefully at an anti-war protest.
You can look up the latest arrest figures on https://ovdinfo.org. It's not official info, but is the best we have.
A new law is currently being fast-tracked through Duma which will allow the state to throw people in prison for up to 20 years for literally any anti-war activity, including peaceful protests.
The country is very close to what it was like in Stalin times, back in 1930s.