my question is that can we really vote in peace without killing and violent ??
The violence is instigated by politicians, it is very obvious. People were willing to conduct themselves in an orderly manner just to ensure that they casted their votes.
Many Nigerians turned up in mass to cast their votes, the youths who have never been involved in elections where out in their numbers to ensure that they made their voices heard, they walked long distances, waited for long hours, stood under the rain, and waited long into the night for their votes to be counted and uploaded, but INEC seems compromised and not independent in their decisions because them just dey do like dem want make the election nor go smoothly, dem dey give room for rigging. They have delayed in uploading some results, made the process not transparent enough, and given room for politicians to take advantage off.
If INEC announces a false result, it will be too obvious because are not stupid anymore and that has the potential of causing a crisis, bigger than we have ever witnessed in Nigeria. To answer your question OP, violence can be avoided by INEC, by ensuring the results announced are as the people voted.